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Newbie questions
jake415
Top  #1 Print Post
Posted on 01/20/2022 3:32 AM
I'm looking to build my first roaster and was hoping to rapid fire some questions.
I read around for the answers but couldn't quite find direct answers.
Is there an estimated air pump pressure rating needed for 350g roasts?
What diameter container is common for the roasting container for 350g batches?
How do you source funnels for connecting blowers to the roasting chamber?
Is there a way to cleanly connect the funnel to the chamber without a rubber gasket?
The most difficult part of this whole process seems to be sourcing material - people get pretty creative around here.

All thoughts welcome, just need more information at this point.

Thanks for helping out
 
jake415
Top  #2 Print Post
Posted on 02/25/2022 2:00 AM
I've figured out where to source stuff by finding various project material lists.

Here are some of those in case others are in a similar position:

http://kostverlor...-tije.html
http://phildawes....e-roaster/
https://homeroast...post_74649
https://docs.goog...edit#gid=0
https://docs.goog...edit#gid=0
https://www.instr...e-Roaster/
https://homeroast...post_72487
 
jake415
Top  #3 Print Post
Posted on 02/25/2022 2:06 AM
Could someone enlighten me on thermocouples?
It seems like responsive thermocouples are important, but I'm not sure which kind to go for.

Here are some that I have found:

1) Exposed tip https://www.amazo...B07D7LN6LP

2) https://coffeecra...ple-probe/

3) Air Thermocouple https://www.amazo...amp;sr=8-2

Also, any advice on placement and whether BT and ET probes should differ?
Edited by renatoa on 02/25/2022 2:24 AM
 
allenb
Top  #4 Print Post
Posted on 02/25/2022 8:04 AM
#3 will work nicely for ET. Nice design.
For bean temp, it will need to be a direct contact type as with #2 but many things will dictate what kind to get. Size of roast chamber, type of roast chamber (asymmetrical or conical) and how much room there is where roasting air path won’t interact with the BT probe very much.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
renatoa
Top  #5 Print Post
Posted on 02/25/2022 8:35 AM
#3 is the standard for gases in the great industry, I am surprised to see nobody uses this sheath in coffee, except the Roest.
But it is big, hard to mount in a 30 mm FB hot air intake pipe, would change significantly the airflow distribution, and surely will introduce turbulence.
Great for exhaust airflow, though !

For the beans, you have attached the contraption I did for the most recent chinese machine I am moding.
As you can see, is an asymmetric roast chamber machine, and what you see is a sandwich made from beans chute, then the light gray is layer of insulator stuff, then follows the naked junction under two layers of aluminium tape.
This design is intended to replicate a commercial versions of surface contact thermocouple, as the one you see here:
https://www.omega...SA1XL.html
The commercial version is made from kapton tape and copper foil or fiberglass, as substrate.
Such kind of surface thermocouple can be mounted on the funnel chute for a symmetrical FB design.

If interested, I can show you a DIY version of the #3 "flute" sheath too.
Also, instead a pipe with holes you can use a spring attached to a #2 probe, almost as effective as #3.
Something like this: https://m.media-a...L1500_.jpg
~~~
renatoa attached the following image:
whatsapp_image_2022-02-25_at_41656_pm.jpeg
Edited by renatoa on 01/09/2023 2:44 AM
 
CK
Top  #6 Print Post
Posted on 02/25/2022 1:40 PM

Quote

jake415 wrote:

Could someone enlighten me on thermocouples?
It seems like responsive thermocouples are important, but I'm not sure which kind to go for.

Here are some that I have found:

1) Exposed tip https://www.amazo...B07D7LN6LP

2) https://coffeecra...ple-probe/

3) Air Thermocouple https://www.amazo...amp;sr=8-2

Also, any advice on placement and whether BT and ET probes should differ?


Roaster908 https://homeroast...ad_id=6723 uses type (1) for all 3 of its thermocouples. Two are used for inlet air temperature monitoring on inlet pipes, and one for the bean temperature probe in the roast chamber. The response times are good, and they seem to read accurately after many months of roasting. The bean temperature probe may foul and need cleaning in the future to maintain accuracy, but for now it still works well even though it's the exposed tip type.
 
jake415
Top  #7 Print Post
Posted on 03/01/2022 4:28 AM
Renetoa your diy versions look pretty sweet. I've got limited time so I'm hoping to buy a thermocouple straight out. Going with the exposed tip ones since they seem to work for CK. All helpful info, thank you.
 
renatoa
Top  #8 Print Post
Posted on 03/01/2022 4:50 AM
Meanwhile the surface diy from image posted above changed a bit, now the junction is inside a 4 mm tube, it was awful responsive for that medium, under 30 microns of alu tape only.
No idea how is CK exposed to the air, he has many secrets in his machine Grin
 
CK
Top  #9 Print Post
Posted on 03/01/2022 11:49 AM

Quote

renatoa wrote:
No idea how is CK exposed to the air, he has many secrets in his machine Grin

Here to solve the mystery...Grin
I use these connectors on my copper inlet pipes to allow for thermocouple placement just before entry to the roast chamber.
https://www.amazo...&psc=1
There are 2 of them for the dual heat inlets... the BT thermocouple is mounted simply by drilling a hole in the roast chamber wall and securing it with a lock nut from the inside.
CK attached the following image:
inlet_thermocouple_placement.jpg
 
jake415
Top  #10 Print Post
Posted on 03/30/2022 3:02 AM
Are there simple ways of using flow thru motors for roaster builds? It seems like tangential bypass motors are the way to go since there is an easy connection point, but I'm not sure, maybe flow through could work somehow. Any ideas?

On a similar note, any suggestions for AC motors for 350g build?
I've tried a bunch of different motors but they are all overpowered (controlled below 50% power for proper agitation).

Here are the ones I have tried (in no particular order):
https://www.amazo...&psc=1
https://www.getpo...-2hp-9-amp
https://www.amazo...&psc=1
https://www.amazo...&psc=1
https://www.amazo...&psc=1

The smaller one for pumping inflatables was under powered. The leaf blower was the closest to usable.

Suggestions, questions, advice much appreciated
Edited by renatoa on 03/30/2022 7:36 AM
 
renatoa
Top  #11 Print Post
Posted on 03/30/2022 7:46 AM
400W leaf blower, exactly this model:
https://www.youtu...LAYmq04lDs
...is good for more than one pound, tested only for greens without heat.

110-130W inflatable, similar to these: www.amazon.com/s?...table+130w
... are good for 250-330 grams, depending on heater.
Used by many guys in our local forum, is the most popular solution for half pound FBs.
 
allenb
Top  #12 Print Post
Posted on 03/30/2022 9:25 AM

Quote

jake415 wrote:

Are there simple ways of using flow thru motors for roaster builds? It seems like tangential bypass motors are the way to go since there is an easy connection point, but I'm not sure, maybe flow through could work somehow. Any ideas?



The easiest method I've found is to utilize a flow thru vac motor. No hoses or adapters needed. All you do is provide a hole in your FB roaster base to allow mounting the vac motor onto the base (motor side of vac motor goes inside of the roaster base and the vac motor has threaded holes for securing it to your base. All other blowers require too much fiddling!
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
jake415
Top  #13 Print Post
Posted on 03/31/2022 1:46 AM
Good advice thanks. I appreciate the specific motors suggestions aswell.
I've decided to make a PVC body around a flow through motor that I got from a bissell vacuum from your suggestion. One thing I'm worried about is the heater melting the motor or PVC pipe. Bit of background, I have a stainless steel pipe which holds the heating element. Is this a concern, and if so, is there a nice way to create a buffer between the stainless steel pipe and the PVC pipe? Custom silicone parts seem expensive and I've considered aluminum duct btw.
 
renatoa
Top  #14 Print Post
Posted on 03/31/2022 2:02 AM
At the air entrance side the heater pipe is not hot at all, actually is really cool.
If inside the tube is a 0.5 mm mica insulator between the heater and tube, even in the middle the outer pipe temperature don't exceed 100C.
The really hot part is the exhaust 1/4 of the tube.
I know a commercial roaster whose blower is mounted in an ordinary PVC molded piece, that clips on the steel tube hosting the heater coil.
3D printed parts are also fine.
 
Annie12
Top  #15 Print Post
Posted on 04/03/2022 10:37 PM

Quote

renatoa wrote:

#3 is the standard for gases in the great industry, I am surprised to see nobody uses this sheath in coffee, except the Roest.
But it is big, hard to mount in a 30 mm FB hot air intake pipe, would change significantly the airflow distribution, and surely will introduce turbulence.
Great for exhaust airflow, though !

For the beans, you have attached the contraption I did for the most recent chinese machine I am moding.
As you can see, is an asymmetric roast chamber machine, and what you see is a sandwich made from beans chute, then the light gray is layer of insulator stuff, then follows the naked junction under two layers of aluminium tape.
This design is intended to replicate a commercial versions of surface contact thermocouple, as the one you see here:
https://www.omega...SA1XL.html
The commercial version is made from kapton tape and copper foil or fiberglass, as substrate.
Such kind of surface thermocouple can be mounted on the funnel chute for a symmetrical FB design.

If interested, I can show you a DIY version of the #3 "flute" sheath too.
Also, instead a pipe with holes you can use a spring attached to a #2 probe, almost as effective as #3. Something like this:
https://m.media-amazon.com/images/I/71RGK0ZKEaL._SL1500_.jpg
~~~


Thanks for sharing the link.
 
olive
Top  #16 Print Post
Posted on 01/08/2023 9:17 PM

Quote

jake415 wrote:

I'm looking to build my first roaster and was hoping to rapid fire some questions.
I read around for the answers but couldn't quite find direct answers.
Is there an estimated air pump pressure rating needed for 350g roasts?
What diameter container is common for the roasting container for 350g batches?
How do you source funnels for connecting blowers to the roasting chamber?
Is there a way to cleanly connect the funnel to the chamber without a rubber gasket?
The most difficult part of this whole process seems to be sourcing material - people get pretty creative around here.

All thoughts welcome, just need more information at this point.

Thanks for helping out


I'm a Newbie too and would love to see answers to the original post.

1) Wondering also if there's a general summary of the different types of FB roasters with their pros & cons?
2) Heating elements - is there a rule of thumb for the wattage needed based on chamber diameter and flow rate?
3) Blower - Is there a guide for blower types with pros/cons? and minimum requirements based on chamber diameter and bean mass?
 
renatoa
Top  #17 Print Post
Posted on 01/09/2023 2:47 AM
There was an attempt/tentative thread to gather all this info in a single place, check here:
https://homeroast...ad_id=6818
 
greencardigan
Top  #18 Print Post
Posted on 01/09/2023 6:53 PM

Quote

jake415 wrote:
Is there a way to cleanly connect the funnel to the chamber without a rubber gasket?


My small conical spouting fluid bed roaster just has the glass tube sitting in the funnel without any gasket. The movement of the glass is loosely restricted by the surrounding metal structure but has a bit of wiggle room. I suspect the air loss under the glass and out of the chamber is negligible.
 
BadHabitRoasters
Top  #19 Print Post
Posted on 01/17/2023 9:02 PM
Another newbie question, I see both straight tapers and bowl shaped funnels for chamber bases. Do the perform different? I’m just starting to gather parts to go along with my TC4 that’s about finished.
 
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